fix build error on Visual Studio 2013 and earlier

tomoaki0705 · tomoaki0705 · commit 94253e8b833f · 2018-02-13T18:30:02.000+09:00
diff --git a/modules/core/src/persistence.hpp b/modules/core/src/persistence.hpp
@@ -12,6 +12,9 @@
 #include <sstream>
 #include <string>
 #include <iterator>
+#ifdef _MSC_VER
+#include <cstdint>
+#endif // _MSC_VER
 
 #define USE_ZLIB 1
 #if USE_ZLIB
